One of the hardest problems for online companies is verifying the age of their users. In the past, there really has been no good technological way to determine the age of a user accessing an online company's website or online services.
This problem has become particularly acute with the passage of the Children's Online Privacy Protection Action (COPPA) (15 U.S.C. §§6501-6506) which prohibits online companies from storing information about users under the age of thirteen without their parent's or legal guardian's permission. In order to comply with COPPA, many online companies query each of their users for their date of birth and, if the response indicates that the user is under thirteen, then prohibiting that user from accessing or using the company's website or online service.
Such authentication procedures can create problems. For example, circumventing or spoofing these kinds of systems is rather trivial. All a user has to do is enter a false date of birth that indicates that the user is older than thirteen in order to access the website. Another common problem is that most online companies do not have a mechanism to allow for storing of information about a under-thirteen child if the child's parent grants (or wants to grant) them permission to store information about the child and still being in compliance with COPPA.